Petroleum treating process



R. L. MURPHEY PETROLEUM TREATING PROCESS Filed June 24, 1957 June 7, 1960 will. A 1 .2

United States atent i" onrelatesftof'the:treatment of residual oils for'L the separation therefrom of -arelatively high quality 10 E fi Us' inyeiifin tn .PfOi/id" a" ofV a high VI lubricating" oil e ifraction', 'such as" anv asphaltic ptbleuiifactiomf 1 h n Y Siill-anothi `ofbject`m of` this invention isl to providef a process for the treatmentof a residual petroleum fraction, such as a long resi'duuni,A wherein there is recovered a finished;k oil fractionrparticularlysuitable asan aircraft engineuoil and the like.

How these andnother 4objectswof this -invention are ac complil'shed will become apparent with reference to the accompanying .disclosure andndravdng wherein there is schematicallyillustrated an embodiment of a' practice of' this inventiondirected'tojthe recovery'of a heavy lubricab. 40 ing oil` fractio'from` apetrol'eum residuum.

Referring nowin' detail toA the drawingf a` crude oil, such an asphaltic crude oil or the like, isji'ntroduced via* line `11-intovcrudestill "for'fractionation unit 12 wherenitisjsubjectedjtofractioal distillation. Froi crude 45 still IZFtlierlins"redoveredoverhead via'line 14 a gas fraction u'snau'y comprising propane and buttate" and the like; 2a naplitha" fraction' viail-ine;` 15V comprising 'the' gasoline constituents originally present in the crude 'oilcharged totthe'crule still, afkerosene fraction via line 16, af gas 50 oil-"fraction via line 18 andadistillate lube oil'or lubricatingoil'-frac`tion vialine'll."` There is recovered as a bottoms fraction :from crudestill 12evia line 20 a long residuu-mgltusually havingan'- initial boiling point greater than abouttGSOf F., morefrequentl'y having an initial boiling 55 point' higher than"700 Fi, land usually amounting to about 565%, more or less; by volume of the original A1e-longfresidu'urn in une acts supplied to; vacuum still* 21' whereiiii'it" isL fractionated into approximately 69 equal parts by volume into a heavy distillate fraction which is recovered overhead from vacuum still 21 via" line 22 and a4 :bottoms fraction or short residuum which l is recovered from vacuum .still 21 via line 24. The

heavydfst-illatefractionremoved overhead from vacuum 65.

Zfi Patented June 7, 1960 Z. plaine and'Ithelike; Generallyeitispreferred to employ liquid? propneor a mixture comprised predominantly of liquidpropane as thelsolvent. Within solvent fractionation zone7 25 the more, parainic constituents inthe heavy: distillate fraction introduced thereinto via line 22 a'repre'ferentially dissolved in thelliquid propane whereas the1 moreasphaltic, :more dense andV heavier portions of said'heavy" distillate: fraction are rejected as a separate phase.

.Solvent fractionation zone 25. may comprise any suitableV meansufor effecting liquid-liquid contact. For example,E4 the solvent` fractionation zone may comprise a combination of mixer-settlers, aRDC (rotating-disc contacter) tower, apackedtower and the like. As indicated in-the accompanying draw-ing; solvent fractionation zone 25 is shown as as--tower suitable -for eiecting countercurrent liquid-liquid contact, the heavy distillate fraction beingV introduced @into the upperr portion of solvent fractionation'zone.' 25 via lin'et22and the liquid solvent (propane).v being 'introduced' into the lower portion of solvent fractionation zone'25 via line 26.

Solvent fractionation zone' 25 is operated under rather severe conditions,'the solvent to charge oil (liquid propane to heavy distillate fraction) dosage ratio in the range Li512; usuallyv inf the' rangeS-,l 0, and at a relatively eleva'ted temperature,:approaching the critical-temperatureof the liquefied normally gaseous hydrocarbon solvent (propane): employed. As indicated hereinabove, propaneispreferred as the solvent. In some instances 0 itisipreferred'to operate solvent fractionation zone 25,

either isothermally in the range 180-205` F. or. with a temperature gradient extending'overthe range 5-2() de: greesfFahrenheit within the solventfractionationzone 25.

AsV indicated, thereA is recovered overhead from sol` 5 ventfractionation zone 25 via line 2Sl a sci-calledpropane distillate phase comprising `the more paraflinic oil originallyY present' in 'the heavy distillate fraction now 1 .substana tiallyA free of Aasphalt,.:bitume`.ns, resinsand. the like.A This propaneifractionated paraflnio oil after separationaof` the li'quid'solvent (propane) therefrom by suitable.' means (not` shown)` is introduced' via line' 28 into solvent re# ningzone 29. Insolvent refining Yzone' 29 the solvent (propane): .fractionated oilissubjected to liquid-liquid contact withra liquid selective solvent which selectively eXtractsthe 'more'arornatic hydrocarbons from the less aromatic` hydrocarbons..` 'Ihesolvent refining" zone 29 maycomprise a 4combination of mixerss:ettlersa rotatingmlisc contactor, a` packed tower and. the like, suitable for effecting liquidilliquid contact between two eountercurrently -ilowing liquid streams. As indicated in the drawing; the solvent fractionated deasphalted oil isA introduced into the lower portion of` solvent rem'ng tower or zone 29 via line 28 and the selective solvent for aromatic hydrocarbons, preferably lfurfural, is introduced intothe upper portion of solvent refining zone 29 via line 30. Althoughliquid lfurfural is lthe preferred selective solvent, other selective solvents such as nin-obenzene,.,Chlorex, `phenol are useful. There is' recove`red overhead'fromf solvent refining' zone' 29 via 'line 31 a solvent refined oil or rainate` This solvent .ren'ed oil, after removal of the selective solvent therefrom by suitable means, not shown, is introduced via line 3'1 into sol vent ,dewaxing zone 32 whereinthe .waxy hydrocarbons are removed therefrom. Dewaxing is preferably eiected by contactingthe oil vcharge to Vdewaxing zone 32 with a liquidfdewaxingisolvent, preferably a mixture of an aliphatic ketone such as methyl ethyl ketone and an oil solvent such as an aromatichydrocarbon, e.g., toluene. The wax separated yfrom the refined `oil is ,recovered from solvent dewaxing zone 32 Via'line 35i.

The resulting-solvent relined dewaxed oil' is"`re'c'ove'red from solvent dewaxingzone 32via"`line'35.

Returning to solvent refining zone 29 there is recovered as a bottoms or extract Ifraction therefrom via line 36 an aromatic extract phase which is suitable per se as cutter stock or fuel oil or after suitable treatment in clay contacting or finishing zone 39 as a red oil recovered The solvent refined dewaxed oil streams recovered via lines 35 and 56 from solvent dewaxing zones 32 and 35, respectively, are preferably combined and the resulting combined oil stream passed via line 58 into clay contacting and/or finishing zone 59. wherein the oil is conrfrom clay contacting or finishing zone 39 via line 40. 5 tacted with a suitable clay treating agent furtheY removal The short residuum recovered as a bottoms fraction of any'objeetionable color bodies and residual resinous from vacuum still 21 is introduced via line 24 into solmaterials therefrom in the usual manner.V There is revent deasphalting zone 41 where it is solvent deasphalted. covered from clay Contacting o1' linlhlng Zone 59 vla The solvent deasphalting operation may be a batch opline 60 a product oil fraction comprising s olvent rened eration, a multiple -vessel operation .or a substantially Solvent doWaXod oil of good Color, of relatively loW on!" continuous liquid-liquid countercurrent treating operation hon ToSiduo and oiihibitlng a; relatively h lgh vlsoolty as indicated in the drawing and as described hereinabove index (VI) and particularly Suitable as an alroraft ensuit with respect to the operation of solvent fractionation oil. i zone 25, wherein the vacuum bottoms or short residuum Tho follow-lng 1S tlllustl'atlvo of a Pl'aotloe of lnvon' is introduced into the upper portion of deasphalting zone ltloIl- A11 amoullt of a heavy Petroleum fractlon W33 or tower 41 and flowed therein in countercurrent liquid- Suhlootod to rather Severo Propane f1 aotlonatlon Milton1` liquid contact .with a suitab1c liquid dcasphalting solvent, poraturo of about 200 F. bv Contact Wlth liquid propano such as liquefied normally gaseous hydrocarbon, eg., proat a propano dosage of about 8-2 volume? of liquid pane, n-butane, isobutane or mixtures thereof, introduced PI'oPaho Por volume of. heavy Petroleum fl'ootlolh There into the lower portion of deasphalting tower 41 via line was recovered as a railinate from the above-described d2.V if dcsircd, thc asphaitic bitinncn or rcsinous tracoperation a propano fractionated oil having a relatively tion rejected from the heavy distillate fraction introduced high ViSooSity index Another amount ofthe Same heavy via line 22 into the solvent tractionating zone 25, with .fraction was subjected to .Propane fractionation. omplovor without the separation of the liquid propane solvent ing tho Samopfopano dosage but undef folatlvoly 1G55 therefrom, .and recovered via line 44 may be combined Severo Condltlous at a temperature of alout 150 F- with thc short rcsidutnn in iinc 24 via line 45. on thc There was obtained from this operation a Propane fracother hand, if desired, this asphaltioor resinous portion tionated oil having a viscosity Vindex definitely less than so rejected from the heavy distillate in solvent fractionathe oil loool/ered from the Propane fractionation Whioh S tion zone 25 may .be separately recovered as product via 30 C21-mod out under the more severe conditions. The test line 44. There is recovered from solvent deasphalting data and the IeSllliS Obtained Which indicate the influence Y zone or tower 41 va line 46 an asphalt product. of tho dogi'oo of Severity of Propane fractionation upon The deasphalted oil recovered overhead from solvent tho quality, Particularly tho Viscosity ndex of tho result- .deasphciting zonc 4i via une 4s, after separation of the ins propano fractionated oil, are Set forth in accompanydeasphalting solvent therefrom by suitable means, not lng Table lshown, is introduced into solvent refining zone 49. Withi TABLE I insolvent refining zone'49 Ithe solvent deasphalted oil is contacted with a liquid solvent which is a selective Propane fractionation long reslduum solvent for the more aromatic hydrocarbons over the Test No K v less aromatic hydrocarbons. A suitable selective solvent 40 Y 1 2 is liquid furfural although other previously disclosed sol- P D tu P t vents. which are selective for aromatic hydrocarbons are Tgfatu: me 'j 820 85 suitable. As indicated in the drawing, liquid furfural is 'gou TOW 199 163 ottom Tower 176 148 introduced via line 50l into the upper portion of solvent Propane Frnctionatcd Yon Yic1d, Percent Basis refining zone wherein it lflows in liquid-liquid counter- 45 Plggetrlamouad ou' 34.1 50.5 current contact with the deasphalted oil introduced thereviscosity, sus/210m'. 93.8 26a into via line 48. There is recovered from the lower VSGOSitY Index 95.5 80.7 portion of the solvent refining zone 49 via line 51 liquid extract phase comprised predominantly of the more aro- I-t was observed that it was desirable to maintain a matic hydrocarbons. This liquid extract, after separa- 50 relatively precise temperature control during the relativetion of thc selective solvent therefrom, is suitable as a 1y high temperature propano fractionation in order to cutter stock, tfuel oil and the like. obtain a relatively high VI propane fractionated oil.

The resul-ting solvent refined oil is recovered overhead Further illuStf-ativo of ia Practico of this invention for .from solvent refining zone 49 via line 52 and then inthe preparation oa relatively high viscosity index aircraft troduced .into solvent dewaxing zone 54 where it is con- 55 engine oil, -a heavy petroleum fraction was subjected to tacted with a liquid dewaxing solvent such as an aliphatic propane vfractionation under relatively severe conditions ketone, eg., methyl isobutyl ketone, preferably a liquid and the resulting propane fractionated oil subjected `to mixture of an aliphatic ketone such as methyl ethyl furti-unal refining, dewaxing and conventional finishing ketone, and an oil solvent, such as an aromatic hydrotreatment such as clay contacting to yield a finished oil. carbon, eg., toluene, benzene and the like. There is 60 rl'here was recovered as a result of the foregoing ,operirecoveredfrom solvent dewaxing zone 54 a wax product ations a relatively high viscosity index oil suitable as an fraction via line 55 and a solvent rened dewaxed oil via aircraft engine oil. The test data observed in the foreline 56. going operations are set forth in accompanying Table II.

TABLE II t Typical Product Hlagtilotcigm vBanned O11 Dewaxed O11 Acid Treated 011 may Clrltamd hilight;

Restduum OllV Processing Conditions (C ountcrcurggftggnm D1ln.Ratio 4:1 Hitt/bbl 3.3#lb`hi itfilihuilitifhm iiggzpyggtgL-W gggggggggga ilihrllitm titi@ iikymd" iifiwhfe' Yicidzopcraticn,rcrccnt 34.1 .II 89.3 19.51 98.0 Est 98.0 Esi oxg. that ,A

TABLE IL Contiuued Pour,

carbon Residue, Percent 0.12-

I Calculated trom percent wax-assuming 35% ollin-w'xake.

Further indicative of the eifectiveness of a practice of 'this invention employing solvent (propane) fractionation in the recovery of a relatively high viscosity index oil from served *that the severity .of propane fractionation and/ or deasphalting showed a marked effect on the viscosity Vindex of uthe solvent fractionated `or deasphalt'ed oil. The `viscosity index of the fractionated or deasphalted oil on a1 RAFFINATE dewaxed basis increased from 63.6 at 83% solvent fractionation yield (12% basis crude) to 72.9 at 19% deasphalting yield (2.7% basis crude) despite the fact that the latter stock had a pour point degrees Fahrenheit lower than the iirst stock. These tests indicated that the viscosity index of a propane solvent fractionated or deasphalted oil from a -given rfraction increases as the severity of the solvent fractionation or deasphalting operation increases. The test results and data observed in the foregoing tests are set forth in accompanying Table III.

TABLE III 800% propane treat, 200% propane wash batch fractionation (deasphaltng) As will be apparent to those skilled in the art many substitutions, variations and changes are possible in the practice of this invention without departing from the spirit or scope thereof.

I claim:

l. A method of treating a heavy asphaltic petroleum fraction which comprises separating said fraction into a heavy distillate fraction and an asphaltic residuum, subjecting said heavy distillate fraction to contact with liqueed propane under severe conditions at a liquid propane to charge ratio in the range 8-10 and at a temperature in the range ISO-205 F. to yield a solvent fractionated oil and a bottoms asphaltic fraction, said solvent fractionated oil being recovered from the aforesaid propane solvent fractionation operation in an amount below about 34% based on said heavy distillate fraction charged thereto, subjecting said solvent fractionated oil to contact with a liquid solvent which is selective for aromatic hydrocarbons to yield a solvent fractionated rafnate, dewaxing said ranate to yield a dewaxed solvent fractionated ranate, solvent deasphalting said asphaltic residuurn to yield a deasphalted oil, subjecting said deasphalted oil to contact with a liquid solvent which is selective for V99.6. ses-.

aromatic hydrocarbons to yield a deas'phalted raffinate, dewaxing said deasphalted rainate to yield a dewaxed deasphalted raffinate, combining the aforesaid dewaxed solvent fractionated raffinate and the aforesaid dewaxed deasphalted raflinate `and subjecting the `resulting combined raffinate to clay contacting to yield a finished dewaxed `refined product oil. l

.-2. A method of treatin-g a heavy asphaltic petroleum -long residuum which comprises subjecting said residuum to vacuum distillation to yield a heavy oil `distillate fraction and an asphaltic bottoms fraction, subjecting said heavy distillate fraction to contact with liquid propane under severe conditions at a temperature in the range -205 F. and at a liquid propane to charge ratio in the range 8-10 to yield a propane Ifractionated oil, said propane fractionated oil being recovered from the afore said propane `fractionation operation in an amount below about 34% based on said heavy distillate fraction charged thereto, subjecting said propane fractionated oil to contact with liquid furfural to selectively solvent extract the more aromatic hydrocarbons from said propane fractionated oil with the production of a propane fractionated rainate, dewaxing said raffinate to yield a dewaxed propane fractionated raiiinate, contacting said asphaltic bottoms frac# tion with liquid isobutane to yield a deasphalted oil, subjecting said deasphalted oil to contact-with liquid furfural to selectively extract the more aromatic hydrocarbons therefrom Iand to yield a deasphalted raffinate, dewaxing said deasphalted raffinate to yield a dewaxed deasphalted raiiinate, combining the aforesaid dewaxed propane fractionated ramnate and the aforesaid deasphalted ratlinate and subjecting the resulting combined raffinate to clay contacting to yield a nished dewaxed rened product oil.

3. A method of t-reating a heavy asphaltic petroleum long residuum which comprises subjecting said residuum to vacuum distillation to yield a heavy oil distillate fraction and lan asphaltic short residuum, subjecting said heavy distillate fraction to contact with liquid propane under severe conditions at a temperature in the range 180-205" F. and at a liquid propane to charge ratio in the range 8-10 to yield a propane fractionated oil and an asphaltic bottoms fraction, said propane fractionated oil being recovered from the aforesaid propane fractionation oper ation in an amount below about 34% based on said heavy distillate fraction charged thereto, subjecting said propane fractionated oil to contact with liquid furfural to selectively solvent extract the more aromatic hydrocarbons from said propane `fractionated oil with the production of a propane fractionated raffinate, dewaxing said rafnate to yield a dewaxed propane fractionated raffinate, admixing said asphaltic bottoms fraction with said as phaltic short residuum yand subjecting the resulting admixture to deasphalting by contact with a liqueed normally gaseous hydrocarbon to yield a deasphalted oil, subjecting said deasphalted oil to contact with liquid furfural to selectively extr-act the more aromatic hydrocarbons therefrom and to yield a deasphalted rainate, dewaxing said deasphalted rainate to yield a dewaxed depane vfractionated rafinate and the aforesaid deasphaltedil -ratiinateand subjecting the resulting combined rainate to clay cont-acting toV yield a finished dewaXed refined product oi1 n.j.....,. Y ,Y n

4. A method of treatirigraheavy aspbaltic betroleuni long resduum which comprises subjecting said residuummm Y Miinate .to yielda dewaxed deasphaltedlraflinate, combinto vacuum distillation to yield substantially equal amounts by volume ofvai Vheavyoil 'distillate fraction and an as-fj"N phaltic short residuum, subjecting said-heavyrdistillate lo fraction t'ofcontact withliqid propaneunder severe pro- W i pane fractionation conditions at a solvent to charge dosage ratio of labout 8:1 4and at a temperature not lower than about 30 degrees Fahrenheit lower than the critical temperature of propane, to yield a propane fractionated 15` oil and `an asphaltic bottoms fraction, said propane fractionated oil Vbeing recovered from the aforesaid propane solvent fractionation operation in an amount below about 34% *based on said heavy distillate fraction charged thereto, subjecting said propane fractionated oil to con- Zio tact with liquid furfural to selectively solvent extract the more aromatic hydrocarbons from said propane fractionated oil within the production of a propane fractionated raffinate, dewaxing said raffinate to yield a dewaxed propane fractionated rainate, admixing said asphaltic bot- 25 toms fraction with said asphaltc short residuum and sub- V,jecting the resulting admixture to deasphalting by contact with aliquetied-normallygaseous hydrocarbon to yield a deasphalted oil, subjecting said deasphalted oil 5 VVto contact with liquid furfural toeselectively extract the moreV aromatichydrcc-arbons therefrom and to yield a deasphalted I-ainate, dewaxing said deasphalted rafing theY aforesaid dewaxed propane fractionated raffinate and the aforesaid deasphalted,raflinate and subjecting the resulting combined rainate'to claycontacting to yield a finished dewaxed renisled Aproduct oil.

References Cited in the le of this patent UNITED STATES PATENTS 1,827,537 Morrell Oct. 13, 1931 1,881,534 Harding Oct. 1l, 1932 1,983,241 Pier et al Dec. 4, 193,4 2,115,960 Lindeke May 3, 1938 2,316,395 Bray et al. Apr. 13, 1943 2,687,982 Baumann Aug. 3l, 1954 2,692,222 Packie Oct. 19, 195.4 2,853,427 Bentley et al. Sept. 23, -1958 

1. A METHOD OF TREATING A HEAVY ASPHALTIC PETROLEUM FRACTION WHICH COMPRISES SEPARATING SAID FRACTION INTO A HEAVY DISTILLATE FRACTION AND AN ASPHALTIC RESIDUUM SUBJECTING SAID HEAVY DISTILLATE FRACTION TO CONTACT WITH LIQUEFIED PROPANE UNDER SEVERE CONDITIONS AT A LIQUID PROPANE TO CHARGE RATIO IN THE RANGE 8-10 AND AT A TEMPERATURE IN THE RANGE 180-205* F. TO YIELD A SOLVENT FRACTIONATED OIL AND A BOTTOMS ASPHALTIC FRACTION, SAID SOLVENT FRACTIONATED OIL BEING RECOVERED FROM THE AFORESAID PROPANE SOLVENT FRACTIONATION OPERATION IN AN AMOUNT BELOW ABOUT 34% BASED ON SAID HEAVY DISTILLATE FRACTION, CHARGED THERETO, SUBJECTING SAID SOLVENT FRACTIONATED OIL TO CONTACT WITH A LIQUID SOLVENT WHICH IS SELECTIVE FOR AROMATIC HYDROCARBONS TO YIELD A SOLVENT FRACTIONATED RAFFINATE, DEWAXING SAID RAFFINATE TO YIELD A DEWAXED SOLVENT FRACTIONATED RAFFINATE, SOLVENT DEASPHALTING SAID ASPHALTIC RESIDUUM TO YIELD A DEASPHALTED OIL, SUBJECTING SAID DEASPHALTED OIL TO CONTACT WITH A LIQUID SOLVENT WHICH IS SELECTIVE FOR AROMATIC HYDROCARBONS TO YIELD A DEASPHALTED RAFFINATE, DEWAXING SAID DEASPHALTED RAFFINATE TO YIELD A DEWAXED DEASPHALTED RAFFINATE, COMBINING THE AFORESAID DEWAXED SOLVENT FRACTIONATED RAFFINATE AND THE AFORESAID DEWAXED DEASPHALTED RAFFINATE AND SUBJECTING THE RESULTING COMBINED RAFFINATE TO CLAY CONTACTING TO YIELD A FINISHED DEWAXED REFINED PRODUCT OIL. 